@Override
  protected Double recomputeMetric() {
    subs.setOntology(getOntology());
    props.setOntology(getOntology());

    setNumerator(subs.recomputeMetric());
    setDenominator(props.recomputeMetric());

    return computeNormalisedMetric();
  }
 @Override
 protected boolean isMetricInvalidated(List<? extends OWLOntologyChange> changes) {
   if (subs.isMetricInvalidated(changes) || props.isMetricInvalidated(changes)) return true;
   else return false;
 }